Note: Descriptions are shown in the official language in which they were submitted.
CA 02734475 2012-03-09
DRIVE ROLLER FOR THE DRAPER CANVAS OF A CROP HEADER
This invention relates to a drive roller for the draper canvas of a crop
header.
BACKGROUND OF THE INVENTION
Draper headers generally include a header frame, an elongate cutter
bar along a front edge of the frame including a cutter bar beam which carries
a
plurality of knife guards for guiding reciprocating movement of a sickle knife
across a
front edge of the cutter bar. On the header is also mounted a draper assembly
including a first and second draper guide roller each arranged at a respective
end of
the draper assembly spaced apart along the cutter bar with an axis of each
roller
extending substantially at right angles to the cutter bar, a draper canvas
forming a
continuous loop of flexible material wrapped around the rollers so as to
define a front
edge of the canvas adjacent the cutter bar, a rear edge of the canvas spaced
rearwardly of the cutter bar, an upper run of the canvas on top of the roller
and a
lower run of the canvas below the rollers. The cut crop thus falls rearwardly
onto the
upper run of the canvas and is transported longitudinally of the header.
Generally,
between the draper rollers there is provided a support plate assembly for the
upper
run of the draper canvas to prevent sagging.
The header of this type can be used simply for forming a swath in
which case the material is carried to a discharge opening of the header and
deposited therefrom onto the ground. Headers of this type can also be used for
feeding a combine harvester so that the materials are carried to an adapter
member
CA 02734475 2012-03-09
2
positioned at the discharge opening of the header for carrying the materials
from the
discharge opening into the feeder housing of the combine harvester. Yet
further,
headers of this type can be used for hay conditioners in which the material
from the
discharge opening is carried into crushing rolls. It will be appreciated,
therefore, that
the use of the header is not limited to particular types of agricultural
machine but can
be used with any such machine in which it is necessary to cut a standing crop
and to
transport that crop when cut longitudinally of the header for operation
thereon.
The draper canvas normally comprises a fabric which is coated with a
rubber material which is then vulcanized after forming of the fabric into the
required
shape and after attachment thereto of transverse slats.
The arrangement shown in US Patent 5,459,986 (Talbot) issued
October 24, 1995 and assigned to the present Assignees has achieved
significant
success and has been used for many years. It provides a seal between an under
surface of a rearwardly extending element of the cutter bar and a front edge
portion
of the upper surface of the canvas.
Not shown in the above patent is the conventional guiding
arrangement to prevent misalignment of the draper canvas on the rollers and
this is
provided by a bead located on the underside of the canvas which runs in a
groove in
the roller.
An alternative arrangement is shown in US Patent 7,472,533 (Talbot et
al) issued January 6 2009 also of the present Assignees and originally
published
April 24 2008. This provides a crop harvesting header with a cutter bar and a
draper
CA 02734475 2012-03-09
3
canvas with a plurality of transverse slats and a resilient strip across a
front edge of
the outer surface in front of the front end of the slats to cooperate with a
rearwardly
projecting element of the cutter bar extending over the upper run of the
draper
canvas to engage the upper surface of said strip to form a seal to inhibit
entry
between the cutter bar and the draper canvas of materials carried by the cut
crop.
There is also provided a bead on the canvas on the surface opposite the strip
within
the width of the strip. The arrangement can be symmetrical with a strip at
each of
the front and rear edges spanned by the slats extending between them, with
beads
on each edge opposite the front and rear strips respectively.
The disclosures of the above patents may be referred to for details of
the construction not provided herein.
SUMMARY OF THE INVENTION
It is one object of the invention to provide an improved design of
header and particularly the drive roller to the draper canvas.
According to the invention there is provided a drive roller for a draper
canvas comprising:
a cylindrical metal roller body having an outer metal cylindrical surface
surrounding an axis of rotation of the roller for engaging a drive surface of
the
canvas wrapped therearound;
and a plurality of hard wear-resistant elements clad onto the outer
metal cylindrical surface of the roller body so as to be raised therefrom;
CA 02734475 2012-03-09
4
the elements having a height and width arranged such that the
elements do not engage into any recesses in the drive surface of the canvas.
Preferably the raised elements are elongate in the form of ribs, ridges
or teeth applied onto the surface of the roller. The term "ribs" is used
hereinafter to
identify these elements but is not intended to imply any particular shape or
orientation of the elements.
Preferably the ribs extend along the roller, that is they are not wholly in
a radial plane of the roller so that each rib extends has a component
extending along
the draper canvas for frictional engagement therewith. Typically the ribs are
parallel
to the axis but they may be helical or may have more complex shapes including
steps or wave shapes. Also a diamond or cross pattern may be used.
The ribs which extend along the roller are preferably angularly spaced
around the roller.
Preferably the ribs are arranged only at ends of the rollers such that
each end of the roller includes a respective section of the ribs which extends
from
the end of the roller to a position spaced from the section of ribs at the
other end.
Preferably the ribs have a height less than 6 mm and more preferably
in the range 1 to 3 mm. Preferably the ribs have a width less than 6 mm and
more
preferably in the range 1 to 3 mm.
Preferably the ribs have an angular spacing around the roller greater
than 10 degrees and more preferably in the range 10 to 45 degrees.
CA 02734475 2012-03-09
Preferably the outer surface is formed of steel and the ribs are formed
of a material clad onto the steel such as by laser cladding using a cladding
material
which creates a carbide content greater than 30% and more preferably greater
than
50%. The upper limit, in practice, for carbide concentration is about 70%.
Once
5 this threshold is exceeded, the amount of binder is not sufficient to create
the
necessary matrix to bind the elements together.
Also, other hard materials can be used as a replacement for the
tungsten carbide to create the raised elements or ribs.
Other technologies that could be used to achieve the raised elements
include welding (tig or mig), thermal spray, brazing, machining, broaching, or
swaging.
The invention also includes the combination of the roller with a canvas
to form a draper assembly having a continuous belt of a fabric material with
an inner
surface for engaging a plurality of rollers and an outer surface for engaging
a
material to be carried thereon; and a drive roller as defined above where the
ribs
having a height and width arranged such that the ribs do not engage into
corresponding recesses in the inner surface of the belt, which surface is free
from
recesses shaped and arranged to receive the ribs.
The invention also includes a
According to a further aspect of the invention there is provided a drive
roller for a draper canvas comprising:
CA 02734475 2012-03-09
6
a cylindrical metal roller body having an outer metal cylindrical surface
surrounding an axis of rotation of the roller for engaging a drive surface of
the
canvas wrapped therearound;
and a plurality of ribs on the outer metal surface of the roller body so
as to be raised therefrom;
the ribs extending longitudinally of the roller at angularly spaced
positions therearound;
the ribs having a height less than 6mm and a width less than 6mm and
being arranged such that the ribs do not engage into any recesses in the drive
surface of the canvas
the ribs being formed of a hard metallic material and a binder and
being clad onto the outer metal surface of the roller.
The invention also includes a header for cutting and transporting a
standing crop comprising:
a header frame;
an elongate cutter bar arranged along a front edge of the frame;
a knife mounted on the cutter bar for cutting the standing crop;
a draper assembly mounted on the header frame rearwardly of the
cutter bar such that cut crop falls onto the draper assembly for
transportation
longitudinally of the header;
the draper assembly including a first and a second draper guide roller
each arranged at a respective end of the draper assembly spaced apart along
the
CA 02734475 2012-03-09
7
cutter bar with an axis of each guide roller arranged substantially at right
angles to
the cutter bar;
the draper assembly including a draper canvas forming a continuous
loop of flexible material wrapped around the rollers so as to define an upper
run of
the draper canvas on top of the rollers and a lower run of the draper canvas
below
the rollers and so as to define an outer surface of the draper canvas which
faces
outwardly of the loop that the outer surface forms the upper surface of the
upper run
and the lower surface of the lower run and an opposed inner surface of the
draper
canvas which faces inwardly of the loop;
the draper canvas comprising a continuous belt of a fabric material
having an inner surface for engaging a plurality of rollers and an outer
surface for
engaging a material to be carried thereon;
at least one of the rollers forming a drive roller for driving movement of
the belt;
the drive roller comprising a cylindrical metal roller body having an
outer metal cylindrical surface surrounding an axis of rotation of the roller
for
engaging the inner surface of the belt;
and a plurality of hard wear-resistant elements clad onto the outer
metal surface of the roller body so as to be raised therefrom;
wherein the elements have a height and width arranged such that the
elements do not engage into corresponding recesses in the inner surface of the
belt,
CA 02734475 2012-03-09
8
which surface is free from recesses shaped and arranged to receive the raised
elements.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which Figures 1 to 5 are taken from prior
art
patent 7,472,533 cited above and are included for completeness only:
Figure 1 is a top plan view of the front part of a header of the prior art.
Figure 2 is a cross sectional view along the lines 2-2 of Figure 1
showing the front part of the header and draper canvas.
Figure 3 is a cross sectional view along the lines 2-2 of Figure 1
showing the rear part of the header and draper canvas and the co-operation of
the
rear guide bead with a groove in the roller.
Figure 4 is a cross sectional view through one edge of the canvas only
taken at location where there is no transverse slat.
Figure 5 is a cross sectional view through one edge of the canvas only
taken at a transverse slat.
Figure 6 is a side elevational view of a roller according to the present
invention to be used in the header described above.
Figure 7 is a cross-sectional view through the roller of Figure 6.
Figure 8 is a cross-sectional view through the roller of Figure 6 on an
CA 02734475 2012-03-09
9
enlarged scale showing the shape of one of the ribs.
In the drawings like characters of reference indicate corresponding
parts in the different figures.
DETAILED DESCRIPTION
The following description is taken from the above prior art patent. Only
those parts of the header which are of importance to the present invention are
shown in the above figures of the present application and the remaining parts
of the
header including the frame structure, drives, ground wheels and the like are
omitted
as these will be well known to one skilled in the art.
The header therefore comprises a frame, one element of which is
indicated at 10 in the form of a beam extending horizontally and forwardly
from a
rear support frame structure (not shown) to a cutter bar assembly generally
indicated
at 11 for support of that cutter bar assembly. The beam 10 forms one of a
plurality
of such beams arranged at spaced positions along the length of the header
frame so
as to support the cutter bar assembly 11 as an elongate structure across the
front
edge of the header.
The cutter bar comprises a generally C-shaped beam 12 which
provides structural support for the cutter bar with the C-shaped beam being
welded
to the front ends of the forwardly extending beams 10. The C-shape beam 12
includes a top plate portion 13, a bottom plate portion 14 and a forward plate
portion
15 which converges from the top and bottom plate portions toward a front apex
16
forming a forward most point of the beam 12. At the apex 16 is welded a
CA 02734475 2012-03-09
longitudinally extending bar 17 which forms a support for a plurality of knife
guards
18 only some of which are shown in Figure 1 for convenience of illustration.
The
knife guards are of course of well known construction and their shape is shown
only
schematically. The knife guards carry a sickle knife assembly 20 having a
5 longitudinally reciprocating bar 21 driving a plurality of triangular knife
blades 22
which sit on the knife guards and reciprocate back and forth across the knife
guards
in a cutting action. Again this construction is well known and therefore
detail is not
necessary.
The cutter bar support beam 12 also carries an elongate angle iron 23
10 which is welded onto the top plate portion 13 on the underside thereof at
the front
edge thereof with the angle iron extending vertically downwardly and then
forming a
support plate 24 extending forwardly therefrom toward the apex 16.
The draper assembly generally indicated at DA includes a first draper
support roller 30 and a second draper support roller (not shown). One of these
rollers is driven by a drive motor (not shown) to effect rotation of the
draper in
conventional manner. The draper assembly further includes a draper canvas 32
in
the form of a continuous loop or band of fabric which is wrapped around the
rollers
at respective ends to form an upper run 33 of the draper canvas on top of the
rollers
and a lower run 34 of the canvas underneath the rollers. The rollers are thus
spaced
longitudinally of the cutter bar and arranged with their axes of rotation
parallel and at
right angles to the cutter bar. The draper canvas 32 has an inner drive
surface 304
engaging an outer surface of the roller 30. The draper canvas thus includes a
front
CA 02734475 2012-03-09
11
edge 35 of the upper run which is adjacent the cutter bar and a rear edge 36
of the
upper run 33 which is remote from the cutter bar and spaced rearwardly
therefrom
thus defining therebetween a flat surface of the upper run for transportation
of the
crop longitudinally of the header. The lower run 34 also includes a front edge
37
and a rear edge. The draper canvas includes a plurality of conventional
transverse
slats 39 which assist in carrying the crop along the draper canvas. Each edge
of the
draper canvas can include a conventional folded seam so as to define a portion
of
the canvas material which is folded back as indicated at 40 with that folded
back
portion being folded back on top of the fabric layer and bonded to the canvas
by the
vulcanization effect in the manufacture of the canvas.
The upper run of the draper canvas is supported by a support plate
assembly 45 which includes a front plate and includes a center plate and rear
plates
which are not shown for convenience of illustration. The front plate includes
a
horizontal top plate portion 46, shown in phantom in Figure 1, laying
underneath the
upper run of the draper canvas adjacent the front edge for supporting that
front edge
in sliding movement across the top surface of that plate. The support plate 46
further includes a vertical plate portion, which extends downwardly from a
front edge
of the top plate portion (not shown in the figures). At a bottom edge of the
vertical
plate portion is provided a lower horizontal plate portion thus forming the
front
support plate into a generally C-shape to provide structural strength so that
the
support plate is essentially self supporting mounted on mounting brackets
(also not
shown).
CA 02734475 2012-03-09
12
The rollers 30 are carried on the support plate 46. Further details of the
brackets and support elements are described in the above patent of Talbot.
The length of the bracket 25 is arranged so that the front edge 49 of
the support plate is spaced rearwardly from the front edge 35 of the upper run
of the
draper canvas. In addition the front end of the rollers 30 is spaced
rearwardly from
the front edge 35 of the upper run of the canvas. This recessing of the front
edges
of the support plate member and of the rollers provides a portion 70 of the
front edge
of the draper canvas which is cantilevered outwardly beyond the support
provided by
those elements.
The beam 12 of the cutter bar is shaped so that the top plate portion
13 extends rearwardly to a rear edge 71 which overlaps the portion 70. The
rear
edge 71 is located therefore at a position rearwardly of the front edge 35 of
the
draper canvas and in a position forwardly of the front edge 49 of the support
plate
and the front ends 65 of the draper rollers. That portion of the draper canvas
therefore which engages the underside 72 of the top plate portion 13 is
unsupported
on its underside and is therefore free to flex downwardly should it be
depressed
downwardly by the presence of material collecting on the under surface 72. The
top
plate portion 13 of the beam 12 is substantially horizontal that is parallel
to the
generally horizontal surface of the upper run. The co-operation therefore
between
the surface 72 of the upper plate portion 13 and the upper surface of the
draper
canvas at the portion 70 provides a seal which inhibits the tendency of
materials to
pass between the draper canvas and the cutter bar. This seal therefore
inhibits the
CA 02734475 2012-03-09
13
build-up of materials inside the C-shape of the cutter bar and between the
draper
canvas upper run and lower run and around the draper rollers which can of
course
cause damage.
At the rear edge 36, the draper canvas is guided on the draper roller by
a V groove 30A in the roller 30 into which projects from the back of the
canvas a V-
shaped guide rib 75 which runs along the inner surface of the canvas along its
full
length.
The construction of the draper of the present invention is shown in
Figures 4 and 5. Thus the draper of the present invention is symmetrical in
that the
draper can be reversed by rotating the draper so that the front edge is turned
to
become the rear edge and vice versa. Thus only the front edge is shown in
Figures
1, 4 and 5 with it being understood that the rear edge is exactly symmetrical.
Thus
in Figure 4 is shown a portion of the draper canvas which includes a base
layer or
sheet 80 which is formed of a fabric sheet 81 which is folded at its edge 82
to form a
portion 83 which is folded back on top of the layer 81 to form an end edge 84
of the
folded back portion 83 which lies on top of the fabric of the layer 81 spaced
away
from the edge 82. The canvas carries a coating or infused rubberized layer in
a
conventional manner. At the edge 82 is provided a strip 86 of a resilient
material.
The resilient material is preferably of the same construction as the
rubberized
coating so that it can be vulcanized with the structure of the canvas and
molded in
place as part of the manufacturing process. The strip 86 has a front edge 87
which
is at or immediately adjacent the edge 82 of the base layer of the canvas. In
the
CA 02734475 2012-03-09
14
embodiment shown the front edge 87 of the strip is immediately coincident with
the
edge 82. The strip includes a rear edge 88 spaced away from the edge 87 into
the
body of the canvas. The strip has an upper surface 89 which is flat and
smooth.
Thus the strip is rectangular with the side edges 87 and 88 being vertical and
the top
surface 89 horizontal. However the strip may be shaped with inclined or
tapered
side edges 87 and 88.
In the example shown the strip has the width of the order of 1" (25mm)
and a height of the order of 116" (4.0mm). The strip thus stands up from the
upper
surface of the base layer of the draper canvas that is the upper surface of
the folded
back portion 83.
On the underside of the draper canvas is molded the bead 75 which is
generally V-shaped so that the sides are tapered downwardly and inwardly to a
bottom surface 75A which is narrower than the base of the bead. The bead is
located at a position spaced from the edge 82 but underlying the strip 86 so
that the
edge of the bead is spaced from the edge 82 by a distance less than the edge
88 of
the strip.
As shown in Figure 5 the canvas also carries slats 39 which stand
upwardly from the upper surface of the canvas to a top edge 39A which is at a
height significantly greater than the height of the strip 86. Each slat
extends
transversely across the draper canvas to a position closely adjacent the strip
at the
respective side edges of the canvas. Thus each slat extends to an end edge 39B
which is spaced from the side edge 82 by a distance greater than the spacing
of the
CA 02734475 2012-03-09
edge 88 of the strip so that the edge 39B of the slat is spaced from the edge
88 of
the strip. The slats 39 are molded integrally with the strip 86 by providing
portions
90 which extend from the edge 39B of the slat to the edge 88 of the strip 86.
These
portions as best shown in Figure 1 have a width equal to the width of the slat
39 to
5 which they are attached and a height (as shown in Figure 5) equal to the
height of
the strip 86. These portions thus act to integrate the structure so that the
slats
connect into the strip to reduce the tendency of the slats to tear away from
the
canvas since the same resilient material forming the strip extends into the
slat and
thus is resistant to stripping or tearing from the base layer of the draper
canvas. In
10 the example shown, the bead 75 has a width at its base of the order of 1/2"
(13mm)
and a height from the under surface of the canvas of the order 1/3" (8mm). The
center of the bead is spaced from the edge 82 by a distance of the order of
2/3"
(16mm). This suitably locates the bead at a position on the canvas for
cooperation
with the groove in the roller at the rear of the canvas as best shown in
Figure 3.
15 Turning now to Figure 2, it will be noted that the side edge 88 of the
strip is substantially coincident with the end edge 71 of the plate 13 so that
the whole
of the strip 86 underlies the plate 13. The presence of the strip 86 provides
an
improved sealing effect between the surface 89 of the strip and the surface 72
of the
plate 13 due to an increase in pressure therebetween. In addition the presence
of
the shoulder or edge 88 provides a raised surface standing upwardly from
surface of
the canvas to inhibit the penetration of material into the space between the
surfaces
89 and 72. The surface 89 is formed as a flat surface molded onto the top of
the
CA 02734475 2012-03-09
16
resilient strip so that the surface 89 can be formed if required. Also it is
or can be
smoother than the surface of the canvas itself to provide an improved contact
surface engaging the surface 72.
It will be noted in Figure 2 that the bead 75 at the front edge is located
at a position spaced forwardly of the edge 49 of the support plate and
forwardly of
the end of the roller. Thus the bead 75 at the front edge of the canvas has no
effect
since it is engaging no component of the roller or support plate. However it
will be
noted that the bead 75 at the rear edge is located in engagement with a groove
in
the roller. In this way wear of the structure takes place at the strip 86 at
the front
edge and the bead 75 at the rear edge. These two components are worn in use so
that the strip 86 at the rear edge and the bead 75 at the front edge remain
unworn.
Rotation of the canvas when the wear has become excessive allows therefore the
canvas to continue in use while the strip 86 from the rear edge is moved for
the
sealing effect at the front edge and the bead 75 is moved to the rear edge for
providing guiding action.
Turning now to the present invention, as shown in Figures 6, 7 and 8
one or both of the rollers 30 and particularly the roller which provides the
drive input
is shown and comprises a cylindrical roller body 301 having an outer generally
cylindrical drive surface 302 surrounding an axis 303 of rotation of the
roller for
engaging an inner drive surface 304 (shown in Figure 3) of the canvas 32
wrapped
around the roller.
CA 02734475 2012-03-09
17
The drive surface 302 is modified by the addition of a plurality of ribs
305 arranged on the outer surface of the roller body with the ribs 305
extending
along at least a part of the body preferably generally in an axial direction.
The ribs
305 extend from an end 306, 307 at the end of the effective drive surface of
the
roller to an intermediate position 308, 309. While the ribs can extend along
the full
length of the roller typically the ends 308 and 309 are spaced outwardly from
one
another leaving a center section 310 of the roller which is bare of the ribs.
The ribs are angularly spaced around the outer surface at an angle of
spacing A. The ribs have a height H and a width W. H is less than 6 mm and
typically lies in the range I to 3 mm. W is less than 6 mm and typically lies
in the
range 1 to 3 mm. A is less than 45 degrees and typically lies in the range 10
to 45
degrees.
The outer surface is formed of a steel sheet wrapped round the axis
and the ribs are formed of a material clad onto the steel. This can preferably
be
done by laser cladding. Other technologies that could be used to achieve the
raised elements or ribs include welding (tig or mig), thermal spray, brazing,
machining, broaching, or swaging.
Laser cladding is a process in which a laser heat source is used to
deposit a desired metal on to a surface. The deposited material can be
transferred
to the substrate by one of several methods including powder injection, pre-
placed
powder on the substrate or by wire feeding. The powder can be a matrix of
tungsten
carbide and binding materials which preferably contains 60% or more of
tungsten
CA 02734475 2012-03-09
18
carbide. However a suitable product can be obtained with a lower level of the
order
of 30-40% tungsten powder for example. Other powders than tungsten carbide
such
as tool steel and high speed steel powders that are also available may also
show
improved wear but to date none have been found to be as effective as the
tungsten
carbide. Some of the other laser cladding processes can be used which use
wire instead of powder. Also further systems are provided which use a hybrid
of
cold spray with a laser assist.
This provides attached ribs which remain in place despite the
significant frictional forces involved in driving the belt on the roller and
also lead to
reduced wear of the roller at the ends where the primary forces are applied
between
the belt and roller. For this purpose, the ribs are formed of a material
having a
carbide content greater than 30% and preferably greater than 50%. A carbide
content greater than 50% is desirable to reduce wear and this can preferably
be
more than 60 or 70%. It will be appreciated that the ribs must last many hours
in
order to maintain the frictional drive to the belt at the required level for
the life of the
system.
The draper canvas typically has two plies of the fabric at the side
edges so that the draper canvas is thicker at this area. Thus the provision of
the
ribs only in this area can provide the required drive which is more aggressive
at
edges. It is of course necessary not only to provide the required wear
characteristics but also to provide an acceptable level of drive friction,
bearing in
mind that a positive drive using inter-engaging members is not acceptable.
CA 02734475 2012-03-09
19
Previously rubber rollers have been proposed and widely used since metal
rollers
have been found to be too slippery when wet. In the present arrangement, the
high
wear characteristics of the added ribs ensures that the material does not wear
away
sufficiently quickly that the roller reverts to an unacceptable smooth metal
roller
which is known to provide insufficient traction.
The shape of the ribs is such that the upper surface is domed or semi-
cylindrical as best shown in Figure 8. This shape of the profile of the ribs
depends on
several factors including the powder used and the parameters in the process
and is
difficult to control. However typically the ribs have no sharp edges at the
sides and
rely on the additional frictional engagement with the belt surface rather then
any
interlocking engagement therewith. However ribs with sharp edges such as of a
rectangular or square cross-section square may be acceptable.
The inner surface of the belt is free from recesses shaped and
arranged to receive the ribs. That is the arrangement is not one where the
ribs are
intended to engage into slots in the belt surface to provide a positive drive
between
the belt and the roller but instead the ribs have a height and width arranged
to be
small such that the ribs do not engage into corresponding recesses in the
belt. Thus
the belt is basically smooth and any roughness or projections are designed not
to
engage the ribs in a positive coupling action.
CA 02734475 2012-03-09
Thus the header of the present invention for cutting and transporting a
standing crop comprises the header frame, partly shown at 10, the elongate
cutter
bar 17 arranged along a front edge of the frame and the knife 20 mounted on
the
cutter bar for cutting the standing crop.
5 The draper assembly DA is mounted on the header frame rearwardly
of the cutter bar such that cut crop falls onto the draper assembly for
transportation
longitudinally of the header. The draper assembly DA includes the first and a
second draper guide rollers 30 each arranged at a respective end of the draper
assembly spaced apart along the cutter bar with an axis of y each guide roller
10 arranged substantially at right angles to the cutter bar.
The draper assembly DA further includes a draper canvas 32 forming a
continuous loop of flexible material wrapped around the rollers 30 so as to
define an
upper run 33 of the draper canvas on top of the rollers and a lower run 34 of
the
draper canvas below the rollers and so as to define an outer surface of the
draper
15 canvas which faces outwardly of the loop.
Other variations which can be used can include where the ribs are full
length, where the ribs are arranged in multiple segments along the roller and
where
the ribs are in spiral form.
